<?php

namespace Aws\Api\Serializer;

use Aws\Api\Service;
use Aws\CommandInterface;
use Aws\EndpointV2\EndpointProviderV2;
use Aws\EndpointV2\EndpointV2SerializerTrait;
use GuzzleHttp\Psr7\Request;
use Psr\Http\Message\RequestInterface;

/**
 * Serializes a query protocol request.
 * @internal
 */
class QuerySerializer {
	use EndpointV2SerializerTrait;

	private $endpoint;
	private $api;
	private $paramBuilder;

	public function __construct(
		Service  $api,
		         $endpoint,
		callable $paramBuilder = null
	) {
		$this->api = $api;
		$this->endpoint = $endpoint;
		$this->paramBuilder = $paramBuilder ?: new QueryParamBuilder();
	}

	/**
	 * When invoked with an AWS command, returns a serialization array
	 * containing "method", "uri", "headers", and "body" key value pairs.
	 *
	 * @param CommandInterface $command Command to serialize into a request.
	 * @param $endpointProvider Provider used for dynamic endpoint resolution.
	 * @param $clientArgs Client arguments used for dynamic endpoint resolution.
	 *
	 * @return RequestInterface
	 */
	public function __invoke(
		CommandInterface $command,
		                 $endpointProvider = null,
		                 $clientArgs = null
	) {
		$operation = $this->api->getOperation($command->getName());
		$body = [
			'Action' => $command->getName(),
			'Version' => $this->api->getMetadata('apiVersion')
		];
		$commandArgs = $command->toArray();

		// Only build up the parameters when there are parameters to build
		if($commandArgs) {
			$body += call_user_func(
				$this->paramBuilder,
				$operation->getInput(),
				$commandArgs
			);
		}
		$body = http_build_query($body, '', '&', PHP_QUERY_RFC3986);
		$headers = [
			'Content-Length' => strlen($body),
			'Content-Type' => 'application/x-www-form-urlencoded'
		];

		if($endpointProvider instanceof EndpointProviderV2) {
			$this->setRequestOptions(
				$endpointProvider,
				$command,
				$operation,
				$commandArgs,
				$clientArgs,
				$headers
			);
		}

		return new Request(
			'POST',
			$this->endpoint,
			$headers,
			$body
		);
	}
}
